The objective of the proposed research is to determine the extent to which T cell receptors bear idiotypes which are present in the B cell repertoire. Based on what is currently known about T cell recognition, the B cell repertoire will be searched in order to determine if B cell clonotypes exist which are analogous to T cells in their specificity. These include antibodies which display haplotype preference by the criteria of differential binding affinity on antigen modified syngeneic or allogeneic cells, and antibodies which are uniquely elicited by cellularly presented antigens. Hybridomas will be constructed from B cells expressing antibody with these specificites in order to obtain sufficient quantities of monoclonal antibodies to produce anti-idiotypic antisera. Anti-idiotypic reagents will be raised against intact Ig as well as immunoglobulin heavy chains. These reagents will be used to screen antigen specific T cells and T cell clones for the presence of T cell receptor which share B cell receptor idiotypes.